Size of Gas Lines

[teg]

Hi just looking at fuel line . I see there are two common sizes 5/16" and 3/8" . I have a Mariner 25 horsepower 1985 outboard motor. Serial # 6611616 what size should be used for fuel line on this motor, kind of confusing. Thank you in advance for your help in this matter.

In His Grace
Teg

 

[minuteman62-64]

Re: Size of Gas Lines

Are you asking about the line from the tank to the disconnect on the motor - or the lines under the cowl?

On mine (1982 30 HP) I have the fuel tank towards the bow. So I used 3/8" line back to the motor. The lines under the cowl are either 1/4" or 5/16" now (after being replaced by a mechanic). I suspect the originals were a metric size, since mine is a Japanese made model.

 

[teg]

Re: Size of Gas Lines

Good Morning to everyone....I had reference to the size of the line from the tank to the motor. thanks you very much minuteman for your help.

In His Grace
Teg

 

[minuteman62-64]

Re: Size of Gas Lines

OK, so my approach would be:
Short run (tank next to transom) - 5/16" OK
Long run (tank in bow area) - go with 3/8" to insure adequate fuel flow

No problem going with bigger diameter in any event - so you could just go ahead an buy 3/8" and use it regardless of the length of the furl line run.

 

[Texasmark]

Re: Size of Gas Lines

No problem going with bigger diameter in any event - so you could just go ahead an buy 3/8" and use it regardless of the length of the furl line run.

+1, however the fuel flow to that engine is not that much so "line drop" wouldn't be all that much regardless of reasonable length. My 115 had a 3/8 line to the tank.

Mark